1. Field of the Invention
The present invention relates to a document cover used to cover original documents placed upon the glass platen over the document illumination station which is part of an electrophotographic copying machine having an external reciprocating carriage assembly. In particular, this invention relates to a document cover for handling and storing a stack of documents which are being manually handled while the copier is at rest or operating.
The prior art through the years shows that different types of document covers have been developed and marketed for copying machines having transparent original document holding platens.
The early document covers were simply flexible, rubber mats, connected to the housing or moving carriage assembly of the copying machine, adjacent to one edge of the transparent platen. The flexible rubber document cover typically has a white undersurface to reflect light passing beyond the borders of the document being copied. Usually, these document covers are fastened at the short edge of the document glass platen, and are manually raised by means of an attached hand grip at the opposing short side of the cover.
Later document covers are hinged at the longer side of the cover, rearwardly located with respect to the operator. These covers are typically rigid, with various forms of construction including foam plastic, with combined strengthening ribs and bends which help to increase rigidity.
Both early and later variations of document covers described are used for copiers having either stationary or reciprocating original document holding platens.
The basic function of the document cover is to clamp an original document firmly to the top of the platen glass in the copier. Whether the glass is stationary or fixed, the covers accomplish the clamping of an original document, however on the moving external carriage copier machines there remains a problem. The problem being in respect to a stack of document material the operator has to place down while operating the machine, and particularly while utilizing the document cover.
To date, document covers as such do not provide means to prevent the stack of documents an operator is working with from sliding off the moving carriage assembly due to abrupt reciprocating terminal motion of the platen carriage assembly. It is additionally desirable to have a capturing pocket device which prevents the same documents from falling from the document cover when the cover is raised or lowered and the machine is at rest.
2. Prior Art
U.S. Pat. No. 4,053,223 issued to Nebiker and Yanofsky discloses a combined document cover and document storage assembly for a copying machine which copies both flat sheets and thick book documents that are placed on a fixed, non-moving platen glass. The cover has a U-shaped pocket for the purpose of holding documents with the enclosing portion of the U located on the rear edge. This cover achieves the purpose of holding a stack of documents placed on the cover for the purpose of retaining them when the cover is upwardly lifted or lowered by an operator.
This patent teaches how to prevent a document or stack of documents from falling from a liftable document cover. However, it does not teach how to prevent documents from falling from a document cover which is mounted upon a platen carriage assembly having reciprocating motion which is abruptly terminated.